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This article has been peer reviewed. It is the author’s final published version in Molecular Genetics and Genomic Medicine, Volume 7, Issue 7, July 2019, Article number e00712.

The published version is available at Copyright © Lund et al.


BACKGROUND: Deficiency in the enzyme β-mannosidase was described over three decades ago. Although rare in occurrence, the presentation of childhood-onset β-mannosidase deficiency consists of hypotonia in the newborn period followed by global development delay, behavior problems, and intellectual disability. No effective pharmacologic treatments have been available.

METHODS: We report 2-year outcomes following the first umbilical cord blood transplant in a 4-year-old boy with early childhood-onset disease.

RESULTS: We show restoration of leukocyte β-mannosidase activity which remained normal at 2 years posttransplant, and a simultaneous increase in plasma β-mannosidase activity and dramatic decrease in urine-free oligosaccharides were also observed. MRI of the brain remained stable. Neurocognitive evaluation revealed test point gains, although the magnitude of improvement was less than expected for age, causing lower IQ scores that represent a wider developmental gap between the patient and unaffected peers.

CONCLUSION: Our findings suggest that hematopoietic cell transplant can correct the biochemical defect in β-mannosidosis, although preservation of the neurocognitive trajectory may be a challenge.

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Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.

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